Pisania gracilis (Sowerby, 1859)
Description: Shell elongate, whorls rounded. Axial sculpture of strong folds, about 14 on the penultimate whorl, becoming weaker on base of body whorl. Strong spiral ribs, 7-10 on penultimate whorl, of width about half of interspaces, override axial folds. Outer lip with strong, low varix; slightly thickened internally, with 11 lirae in mature shells. Inner lip smooth, with a ridge beside anterior canal. Anterior canal deep, posterior canal well defined, bordered by ridges on outer lip and parietal wall. Colour uniformly fawn or cream.
Size: Up to 11 mm in length.
Distribution: Endemic to Australia; Cape Moreton, Qld, to Ulladulla, NSW.
Habitat: Known mainly from beach shells, with a few specimens from down to 143 m. Uncommon.
Synonym: Pisania unicolor (Angas, 1867) is similar to this species. It is reported by Ponder (1972) as having a shorter, slightly broader shell, less convex whorls, weaker axial ribs which are usually weak or absent on the body whorl, and more numerous, closer spaced spiral cords. However, these sculptural features fall within the range of variation of P. gracilis, so P. unicolor is probably a synonym.
Copyright Des Beechey 2000